With the continuous development and improvement of electronic technologies, terminals such as mobile phones and tablet computers have become an indispensable part of people's lives. People can not only use these terminals to communicate, but also can play video, file, camera, play games, and more.
As people continue to pursuit the display on high brightness and energy saving, four primary colors (Red Green Blue White, RGBW) algorithm system came into being, that is, the original primary colors (Red Green Blue, RGB) sub-pixel system becomes the RGBW sub-pixel system; first, the received image data is converted from the gray-scale domain to the luminance domain to improve the calculation precision, and then the received RGB data is converted into the RGBW domain. After that, the sub pixel rendering (SPR) technology and the specific mapping relationship, and then through the brightness of the gray-scale domain to the conversion process will be RGB graphics data into RGBW graphics data, but this method also has some problems, during the process of RGB data of image being converted into RGBW, due to the panel process and pixel limits, the gain of the saturated color is actually less than the gain of unsaturated color, which makes the screen appears a phenomenon that the saturated color is darker than the unsaturated color during the screen display. For the picture with a higher saturated color ratio, the image displayed by the RGBW system is darker than the image displayed by the RGB system, which may not be able to achieve the expected effect and may reduce the display effect of the terminal due to the high demand on the picture.